The objectives of the research proposed in this application pertain to three levels of cell bioenergetics. In the first set we propose to stuy the origin, mechanism, quanitative relationships and the function of the protons transported outward across the membrane of mitochondria during cell respiration, a process which is believed to be a primary event in the transformation of energy released from oxidation of fuel molecules into ATP and other forms of cell energy. Secondly, we propose to extract, purify, charcterize, and reconsstitute the mitochondrial membrane transport systems for ATP, for Ca2 ions, and for ornithine, an important metabolite in the biosynthesis of urea. The mechanism o the coupling of these transport systems to the oxidation of cell fuels will also be studied. In the third set of objectives we propose to examine the biological role and efficiency of mitochondria in the regulation of ca2 ions-dependent cell activities, such as glycolysis, respiration, muscle contraction, an mobilization of fuels. We shall als examine the role of mitochondria in normal and pathological calcification of tissues. We also hope to work out a method for determining the efficiency of conversion of respiratory energy into ATP in intact tissues or cells, which may be useful in study of thyroid disease, obesty, and other forms of metabolic pathology.